Ec tds meter . . . Help needed.

WhitestOfWidows said:

I have just got a 3 in 1 meter and am a litttle confused as to which setting to use it on and how to read it , i hear of ppl using 1500 ppm etc etc but this meter deesnt read in thousandths, and the instructions are a bit scientific for my brain, have i even got the right type of meter?? heres the info on it

HM Digital COM-100: Waterproof EC / TDS / Temp Combo Meter

This TDS Meter is ideal for all water quality testing, water purification applications, wastewater regulation, aquaculture, hydroponics, colloidal silver, labs & scientific testing, pools & spas, ecology testing, boilers & cooling towers, water treatment and more.

FEATURES
Measures electrical conductivity (EC), total dissolved solids (TDS) and temperature.
Three different calibration options (KCl, 442TM, NaCl), each with its own non-linear conversion factor.
Automatic Temperature Compensation (ATC) using three temperature coefficients
Waterproof housing (IP-67 rating)
Measurement Range: 0-9990 µS; 0-8560 ppm (auto-ranging).
Digital Calibration (push button)
Auto-off function, data-hold function and low-battery indicator.
Display: large and easy-to-read LCD screen includes simultaneous temperature reading.
Factory Calibrated: The COM-100 meter is calibrated with a 1413 µS solution. The meter can be recalibrated with digital calibration using the push buttons, rather than a screwdriver.
Includes a cap, batteries and lanyard.

SPECIFICATIONS
EC Range: 0 - 9990 µS
TDS Range: 0-8560 ppm (mg/L)
Temperature Range: 0-80 °C; 32-176 °F
Resolution: 0-99: 0.1 µS/ppm; 100-999: 1 µS/ppm; 1000-9990: 10 µS/ppm. Temp. resolution is 0.1 °C/F
Accuracy: +/- 2%
EC to TDS Conversion Factor: Non-linear conversions for KCl, 442TM or NaCl solutions,
set by the user.
Calibration: Digital calibration by push button.
Probe: Detachable platinum electrodes
Housing: IP-67 Waterproof (submersible; floats)
Power source: 3 x 1.5V button cell batteries (included)
Dimensions: 18.5 x 3.4 x 3.4 cm (7.3 x 1.3 x 1.3 inches)
Weight: 90.7g (3.2 oz)


is this any good for the job??

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fishman said:

There is two ppm setting ,Can anyone tell me the difference in them?

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Someguy15 said:

Difference is what chemical it is basing it's PPM 'guess' off of. All PPM meters are EC meters that convert. I prefer to use the NaCL EC setting on mine, and then convert to ppm (.5) or ppm (.7) depending on situation using the scale below. The only difference between the 3 ec settings are the temperature compensation curves. I choose EC NaCl.

(EC(mS))—(PPM.5)—(PPM.7)—(CF)

.4———200————-280———–4—–seedling/ rooted clones
.6———300————-420———–6—–
.8———400————-560———–8—–veg
1.0——–500————-700———-10
1.2——–600————-840———-12
1.4——–700————-980———-14
1.6——–800————-1120———16—–aggressive
1.8——–900————-1260———18
2.0——–1000————1400———20—–super aggressive
2.2——–1100————1540———22
2.4——–1200————1680———24

​

So if it reads 956, your ec is .956.... if it reads 104 and the x10 symbol is blinking, this is 1.04 EC, make sense?

Reason I prefer EC is it never changes. Too often people throw around PPM measurements and never note if its the .5 or .7 scale. As you can see this makes a big difference... at 1EC, the (.5)ppm is 500, but the (.7)pmm is 700. If the person doesn't mention what scale, we really have no clue which to choose.

With this meter you can measure EC (NaCL, 442, KCL) or PPM (NaCl & KCL are .5 scales) and (442 is a .7 scale)

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